ISOLATION AND ANALYSIS OF CINNAMIC ACID 4-HYDROXYLASE HOMOLOGOUS GENES FROM A HYBRID ASPEN, POPULUS-KITATAMIENSIS

Cinnamic acid 4-hydroxylase (CA4H) is the second enzyme involved in ph enylpropanoid biosynthesis and is a member of the cytochrome P-450 sup erfamily. Three CA4H homologous genes, cyp73a, cyp73b, and cyp73c, and a cDNA clone of cyp73a were isolated from a genomic library and a cDN A library of a hybrid aspen; Populus ktakamiensis, and were characteri zed. They might be interrupted to two introns each. cyp73a and cyp73b were very similar to each other not only in coding regions but also in non-coding regions. Southern blot analysis showed that four homologou s genes for CA4H constructed a small gene family in the diploid genome of P. kitakamienis. In the promoter regions, there were many common c is-element-like sequences in phenylpropanoid biosynthesis genes.